If a surgeon needs to access a kidney in a patient, e.g. in order to remove a kidney stone, and if a direct surgical intervention has been dismissed, the natural route of entry is as follows: going through the urethra into the bladder, passing the bladder, going beyond the ureteral meatus and then going through the ureter to reach the kidney.
The positioning of an access sheath has traditionally been performed by a quite restrictive method explained below.
Following the insertion of an endoscope into the bladder to locate the ureteral meatus, a first radiopaque guidewire is driven up to the bladder and then, with the aid of the endoscope targeting the ureteral meatus for introduction of the first guidewire into the ureter.
After the first guidewire has been set up, a radiopaque double channel ureteral probe is engaged by one of its both channels onto the first guidewire and it is driven up to the ureter. Through the other channel of the ureteral probe, a second guidewire is introduced until it too reaches the ureter. Then the ureteral probe is removed to leave the first and the second guidewires in the patient, one guide now functioning as a working guidewire and the other one functioning as a security guidewire. The security guidewire is then fixed to, and held in place on, the patient. During these first steps the radiopaque components have been visualized to check their positions by means of an X-ray cannon connected to a monitor.
The access sheath to be positioned sits on, or is threaded onto, an introducer element projecting proximally beyond the access sheath, the introducer comprising a channel. The access sheath on the introducer is then guided onto the working guidewire through the channel and the sheath is then driven up to a position between the bladder and the kidney, however relatively nearer to the bladder. The introducer element and the working guidewire are then removed to leave behind in place only the access sheath, and near it, the security guidewire that can be used in case of unforeseen difficulties.
The course of all these steps of positioning the access sheath highlights the fundamental problem behind the present invention: reducing the number of positioning steps in order to save time and reduce the risks for the patient involved with the procedure while limiting the number of necessary components (including the working and security guidewires, the ureteral probe for positioning the security guidewire and the dilator element).
WO2009/127216A1 relates to a catheter for positioning an access sheath and a security guide next to the sheath for an intervention in a difficult-to-access area within the body, comprising, along the catheter, at least one security channel for positioning a guide, characterised by the fact that the security channel is a channel extending between an outer hole and an inner hole, the wall of the catheter extending between both holes of the security channel being arranged to open under the action of a peel strength directed from inside to outside the channel.